DEVELOPMENT OF A VIRTUAL ITINERARY WITH HBIM AND GIS

: This study explores the potential of Heritage Building Information Modeling (HBIM) and Geographic Information Systems (GIS) for assessing tourist visitation and managing public use of heritage buildings. By integrating these tools, the research aims to improve preventive maintenance and conservation management in culturally significant buildings and urban outdoor spaces. The findings demonstrate the value of HBIM and GIS in handling spatial information and facilitating reliable decision-making for tourist itinerary design and visitor flow management. By examining three buildings of the highest degree of protection as assets of cultural interest, the information obtained can be extrapolated to a municipal management network that encompasses numerous urban models. The integration of databases enables the combination of data at different scales, from the building level to the territorial level, involving all relevant stakeholders from various disciplines. The results highlight the importance of using digital tools in the context of heritage architecture and public use management, promoting more sustainable practices in the preservation and conservation of our cultural heritage.


INTRODUCTION 1.1 Background
This paper aims to present the initial outcomes of a research project focused on developing a prototype database using 3D models generated through GIS and HBIM methodologies.This research is motivated by the growing importance of cultural heritage conservation and the need for innovative, technologydriven solutions to address challenges in the cultural tourism sector.As a case study, the city of Valencia, Spain, with one of the largest historic centres in Europe, is examined in detail.(Figure 1) Cultural heritage conservation is a vital aspect of sustainable development within the cultural tourism sector, encompassing public administrations, the scientific community, and society at large.With increasing public interest in cultural heritage and uncoordinated planning of heritage assets, there is a risk of degrading these valuable resources (Garcia-Hernandez, 2003).Furthermore, the recent pandemic has underscored existing deficiencies in the sector, particularly the lack of adequate planning and coordination among different actors, such as heritage, urban, and tourism, as well as the absence of technological means in public use management.
To address these challenges, digital twins, particularly 3D models with semantic information of cities and historic centres, have emerged as essential tools for risk control, planning, analysis, and visualization.However, the rapid accumulation of data creates challenges in handling different temporal versions of virtual 3D models, especially for cities and historic centres.Many existing city modeling implementations lack the ability to process changes automatically and efficiently, including visualization, semantics, geometry, topology, structure, level of detail (LoD), auxiliary means, and scope.
To overcome these limitations, this study proposes a specific conceptual approach for introducing necessary information for stakeholders in an interoperable manner.It incorporates two mathematical methods from Nguyen and Kolbe1 (2022) for counting people and monitoring sensor-derived environmental data.Salvador-García's (2020) research demonstrates the feasibility of managing public use of a monument through HBIM and GIS.
The prototype database incorporates various HBIM models for buildings, urban spaces, streets, and squares.Additionally, documentary information for different virtual alternative itineraries in the urban environment will be linked to a GIS model of the Historic Center.By integrating GIS and HBIM methodologies, the project aims to develop a comprehensive, technology-driven solution that addresses the challenges faced by the cultural tourism sector, ensuring the sustainable conservation and effective management of heritage assets.

2 Literature Review
The literature review examines the development and application of HBIM and GIS systems in managing public use of heritage assets, following the framework proposed by Zupic and Čater (2015).This approach allows researchers to understand the current state of the art, relevant previous studies, and to focus on specific aspects to maintain both qualitative and quantitative attention.
GIS has become a powerful tool in urban planning and resource management, leading to interoperability tests with BIM in various cultural heritage contexts.Key studies on HBIM and GIS capabilities, such as those by Pavel (2016) and Yang et al. (2020), provide valuable insights into the subject.The integration of HBIM in GIS has also been used in geographic contexts, with Martín and Murrillo (2020) evaluating potential risks to heritage assets in archaeological areas.Albea et al. (2016) have advanced in creating interactive maps of heritage complexes for public consultation through the Spatial Data Infrastructure Geoportal.Bruno et al. (2020) developed a web information system integrating BIM and GIS data to analyse the historic city and its main buildings over time.
BIM models are known for detailed building information specific to a site or location, while GIS provides information about the territory and infrastructure surrounding the building or site.Chenaux et al. (2019) discussed the integration of BIM with GIS as part of the workflow in creating Virtual Historic Dublin, designing an interactive 3D model of Dublin's historic centre.
Studies incorporating diverse information about heritage asset management, such as Fassi et al. (2016), confirm HBIM's potential in managing building maintenance throughout its lifecycle.In the same vein, Bruno et al. (2018) made progress in documenting injuries through monitoring and sensor placement, significantly advancing preventive conservation and action planning.Martín and Murillo (2020) extended the application of HBIM to the field of archaeology.
The British Guide Historic Building Information Modeling (HBIM) (2017) suggests that HBIM is an innovative system that enhances cultural heritage information management (Arayaci et al., 2017, Puerto, 2021).By facilitating collaborative work, geometric, semantic, and documentary information of heritage assets from various disciplines is gathered in a common repository for conservation and management.HBIM can also contribute to maintenance tasks and cultural dissemination (Lo Turco et al., 2016).However, few studies have focused on these applications (Salvador-García, 2020), who examines recreational carrying capacity (RCC) as defined by Manning and Lawson (2002) -the maximum acceptable visitor impact level in a heritage space before resource conservation and visitor experience quality are compromised.
Currently, limited research exists on the use of HBIM and GIS methodologies for managing tourist visits, with the exception of Salvador's team's work (Salvador-García et al., 2020).

Research Objectives
This research aims to present partial results of the efforts to develop a prototype information repository using the ArcGIS Pro platform.This involves the application of GIS and HBIM methodologies and associated technologies, including reality capture (RC), data processing, scanning registration, 3D modeling, and information for preventive maintenance.The study is conducted within the context of one of the strategic actions of the Special Protection Plan of Ciutat Vella for managing the Historic Center of the Municipality of Valencia (Spain), approved on February 13, 2020, PEP Ciutat Vella, 2022.
The objective is to create a 3D-GIS model of a portion of Valencia's Historic Center, encompassing complex structures such as the Metropolitan Cathedral, the Royal College Seminary of Corpus Christi, the medieval complex of Sant Juan del Hospital, and the surrounding urban environment.This model will be used to estimate visitor volume accessing not only specific cultural heritage site but also to analyse their mobility patterns through direct counting methods based on audio-visual images recorded by fully anonymized mobile phones.The study builds upon the innovative use of HBIM applied to the church of Sant Juan de Hospital de Valencia, with the results extrapolated to the other two buildings and unique outdoor spaces within the urban environment.
Additionally, this study emphasizes the delineation of the protection environments for the three monuments situated within the urban morphological structure.This delineation allows for the identification and distinction of various peculiarities that define the urban fabric while recognizing the developmental evolution and motivating elements.The selected areas for study correspond to the central area of La Seu-Xera, Calle la Paz's location, and the former University area ((López González et al., 2020)

METHODOLOGY
To accomplish these objectives, a methodology was designed alongside the accompanying work technology to address a problem related to heritage architecture and its public use.The Design Science Research (DSR) method was chosen as it follows the five stages suggested by Vaishnavi et al. (2004) and Chaves et al. (2016) for Design Sciences: 1. Identify the problem: through the analysis of the scientific literature.2. Understand the problem: through the analysis of cultural tourism planning in the proposed case studies, with all three cases under the same management body.3. Develop a solution: by creating a Protocol that integrates HBIM-GIS functions related to cultural tourism planning and property conservation.4. Implement the solution: by applying the protocol to case studies. 5. Evaluate the solution: by assessing the Protocol's effectiveness, identifying potential changes and improvements, and analysing the exportability and transferability of results to other situations.
Figure 2. illustrates the process of the methodology adopted by this research.Direct methods include in situ counts, counts from photographs and still satellite images, automated counts using mechanisms (turnstiles, infrared, etc.), and counts from automated photographs or video cameras located in strategic places.The emergence of new image-based artificial intelligence technologies has enabled the automation and optimization of people quantification (Wang et al., 2020).
With these studies as precedents, the implementation of information using the referred tools became more accessible, facilitating the creation of the first 3D-GIS model prototype for a Historic Center.

RESULTS
The results obtained in this first stage of development are the following:

Reality Data Capture
The process of capturing geometric spatial reality and gathering pertinent information for cultural management and maintenance was conducted in the area encompassing the Seu-Xerea and Universitat neighbourhoods, where the three buildings are situated.A Leica RTC360 laser scanner and its accompanying Cyclone software were utilized for this purpose.It is important to note that documenting heritage buildings necessitates specific Levels of Detail (LoDs) or Levels of Development.The outcome of the laser scanning process was the creation of a 3D point cloud-based virtual itinerary (Figure 3), which was georeferenced using predefined survey benchmarks obtained with a total station.Point clouds were subsequently exported, connected, and interrelated through a merged BIM model.Additionally, point clouds were implemented in Revit for digital modelling (Figure 4).Data acquisition for the Real Colegio Seminario de Corpus Christi, Metropolitan Cathedral, and the Church of Sant Juan of the Hospital performed using FARO Focus Premium, focus 360, Focus 3D, and FARO Freestyle handheld scanner.The collected data was subsequently processed using the FARO SCENE software.

Collection of Tourist Information
The process of collecting tourist information involves automatically counting people using video images captured by two mobile phones, followed by image processing and the application of artificial intelligence for automatic people detection.The data gathered so far are from the Sant Juan del Hospital complex and the Metropolitan Cathedral.The mobile The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLVIII-M-2-2023 29th CIPA Symposium "Documenting, Understanding, Preserving Cultural Heritage: Humanities and Digital Technologies for Shaping the Future", 25-30 June 2023, Florence, Italy phones utilized were basic Samsung devices (Galaxy A20e) with 32 GB of internal storage and a 5,000 mAh fast-charging battery.The captured images were processed using a Python script that enabled automatic people detection through artificial intelligence.This was made possible by the open-source CVLIB library (Ponnusamy, n.d.), which detects people and other objects in photographs using artificial intelligence algorithms.In this instance, the YOLOv3 model trained on the COCO dataset was employed (Collado et al., 2022) (Figures 5 and 6).

Incorporating Models into GIS
The BIM models have been integrated into GIS through the ArcGIS online platform, which facilitates the combination of 2D and 3D map models from various sources within an intuitive interface.Simultaneously, it enables visualization, analysis, image processing, data management, and integration of information generated by the involved parties.A preliminary 3D-GIS model prototype has been developed, which incorporates the first LoD-200 HBIM models of the three buildings, along with information on the itineraries of the surrounding urban environments (Figure 7).
The three HBIM models of interest are at different Levels of Detail (LoD).The cathedral is at a basic geometric level (Figure 8), while the Seminary College of Corpus Christi is at the geometric level with textures obtained from the point cloud, both in the process of being implemented in Revit (Figure 9).A complete model of the Church of Sant Juan of Hospital is available in Revit (Figures 10 and 11).

DISCUSSION
The results pertaining to the calculation of recreational carrying capacity (RCC) demonstrate that the combination of HBIM and GIS serves as a highly efficient digital tool.This is because the system enables improved handling of spatial information by linking semantic data, which in turn facilitates a comprehensive understanding of the subject.(Figure 14 and 15.)Moreover, it is evident that the Autodesk Revit software allows for the integration of geometric and semantic information generated by the stakeholders involved in public use planning and management into the HBIM model.Concurrently, it offers reliable support for decision-making in designing tourist itineraries and managing visitor flow.Additionally, associated with improper visit management before they materialize, thus reducing the time and cost invested for achieving more sustainable management.

CONCLUSIONS
This study demonstrates the potential of HBIM and GIS tools in assessing tourist visitation within building interiors and urban outdoor spaces.By integrating these tools and fostering their interoperability, we can effectively manage public use of heritage buildings and contribute to preventive maintenance and conservation management.
The research has shown that combining HBIM and GIS models offers a comprehensive approach to handling spatial information and facilitates reliable decision-making for tourist itinerary design and visitor flow management.The ability of HBIM to virtually analyse different alternatives can help anticipate and resolve risks associated with improper visit management, ultimately reducing time and costs for more sustainable management.
By examining three culturally significant buildings, the information obtained can be extrapolated to a municipal management network that encompasses numerous urban models, both buildings and urban spaces of historical heritage interest.The integration of databases enables the combination of data at different scales, from the building level to the territorial level, involving all relevant stakeholders from various disciplines.(Figure 12.) Figure 12.Various ArcGIS milestones.The most significant aspect is the footprint of the three buildings of the three models imported from Revit, which can be compared or used to generate statistics or shared tours.
In conclusion, this research highlights the value of using HBIM and GIS tools in studies of tourist frequentation, not only for building interiors but also for urban outdoor spaces.The integration of these databases allows for data combination at different scales, contributing to a more comprehensive understanding and management of heritage sites.This work paves the way for further exploration of these digital tools in the context of heritage architecture and public use management, promoting more sustainable practices in the preservation and conservation of our cultural heritage.(Figure 13.)

Figure 1 .
Figure 1.Orthophotos with the delimitation of the area of the historic Centre of the Metropolitan: (1) the Cathedral; (2) the medieval complex of San Juan of the hospital; (3) the Royal College Seminary of Corpus Christi.

Figure 2 .
Figure 2. The results presented in this contribution correspond to stages

Figure 3 .
Figure 3. Registration of clusters of laser scans of cultural routes to create a point cloud in the Leica® Cyclone Register 360 software.

Figure 4 .
Figure 4. Integration of point clouds of the Metropolitan Cathedral of Valencia the Royal College Seminary of Corpus Christi and the medieval complex of San Juan of Hospital made in Autodesk® Revit software.

Figure 5 .
Figure 5. Distribution of the visual recording devices in the 3D model located on the balcony of Sant Juan Hospital, Valencia, relapse to the street Trinquete de Caballeros.

Figure 6 .
Figure 6.Automatic detection of passers-by from Piazza di Naples and Sicily (left) and from Piazza San Vicente Ferrer (right) towards of Sant Juan Hospital, Valencia.

Figure 7 .
Figure 7. ArcGIS environment and delimited with colours.The protected environments of each building superimposed on a layer of volumes of all the buildings of the city obtained from the cadastre.

Figure 8 .
Figure 8.The Cathedral geometric model in the GIS Platform.

Figure 9 .Figure 10 .
Figure 9. Seminary College of Corpus Christi geometric model with textures obtained from the point cloud.

Figure 11 .
Figure 11.Complete model of the Church of San Juan del Hospital inserted in the GIS Platform

Figure 13 .
Figure 13.Diagram of the conclusion the potential of HBIM and GIS tools in assessing tourist visitation.

Figure 15 .
Figure 15.View proposed sightseeing milestones embedded from Revit software to ArcGIS platform the Church of Sant Juan del Hospital.
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLVIII-M-2-2023 29th CIPA Symposium "Documenting, Understanding, Preserving Cultural Heritage: Humanities and Digital Technologies for Shaping the Future", 25-30 June 2023, Florence, Italy